Capsules and machines functioning according to the above-mentioned principle have existed for several decades.
The U.S. Pat. No. 2,899,886, U.S. Pat. No. 2,968,560, U.S. Pat. No. 3,403,617 and U.S. Pat. No. 3,607,297 describe devices in which the capsule is initially perforated in several places, then passed through by water under pressure.
The capsule described in the patent CH 605 293 or in the patent EP 0 242 556 B1 comprises a membrane in its lower part. Water under pressure is initially introduced in the upper part of the capsule, which brings about a swelling of the capsule, principally at the level of the membrane. Starting from a certain pressure, the membrane tears, thus permitting the flow of a water-coffee mixture.
Other capsules provided with a membrane are described in the following patent documents: EP 0 468 079 A, EP 0 806 373 A, EP 0 554 469 A.
One of the objectives of the present invention lies in an improvement of the circulation of the liquid through the capsule, and the invention aims to prevent liquid from flowing along the side wall of the capsule and also aims to optimize the “capsule-capsule holder” pair by proposing specific means cooperating with one another to obtain an optimized function.
These objectives are realized with the capsule and the device as defined in the claims.
According to the present invention, to respond, in particular, to the problems of tightness of the existing capsules, there is provided as a minimum, on a portion of the capsule, for example on the flange thereof, deformable element which cooperates with a corresponding deforming member placed on the capsule holder (or on a fixed element or a portion of the said capsule holder).
Typically, the deformable element can be a deformable collar on the flange of the capsule. This collar can be formed in the said flange or can be added thereon. Preferably, this collar (the deformable element) undergoes a plastic deformation during the use of the capsule. Alternatively, an elastic deformation could be envisaged.
In a corresponding manner, the deforming member of the capsule holder can be a groove formed in the lower edge of the said capsule holder, the said groove permitting the collar to be deformed in a directed manner. This groove can be of any shape, but preferably it is such that it promotes a directed deformation of the deformable element of the capsule. Preferably, this groove has a rounded shape.
Furthermore, additional means can be provided (for example a specific material or a shape) on the capsule holder (in particular on the deforming member), the resistance of which is adapted to that of the deformable element of the capsule, for example to that of the collar, such that only deformable elements having a maximum predetermined resistance are correctly deformed by the capsule holder. According to this principle, the use of a capsule of which the collar would have a resistance greater than that which is predetermined would result in a temporary or permanent deformation of the capsule holder (namely in particular of the deforming member), or the part carrying the deforming member. This would permit the prevention of the use of capsules non-adapted to the capsule holder (and to the machine) concerned, by adversely affecting in particular the tightness.
An effect of the present invention is that it permits an “optimization” of the capsule-capsule holder pair in that the means which are provided are provided in a manner which optimizes the functioning of the machine, since an optimum pair is obtained of the elements constituting the system and the deformation of the deformable means reinforces the tightness of the system.
Several equivalent ways of forming the means according to the invention are possible and the example embodiments in the present application are given by way of illustration. Of course, they must not be considered as being restrictive, and variations are possible within the framework of the present application, in particular by the use of equivalent means.